What Causes a Braided Plumbing Line to Leak?

Braided plumbing lines connect supply valves to plumbing fixtures, such as faucets. The term braided refers to the line's exterior covering, a flexible sheath of woven metal. Leaks can occur at several parts of a braided plumbing line, usually because of punctures, deterioration or prolonged stretching. If you learn to identify the cause of your braided line's leak, you can determine whether to repair it or replace it.

Pipes and valves underneath sink
credit: Jupiterimages/Photos.com/Getty Images
Braided supply lines connect to valves beneath sink fixtures.

Loose Nuts and Cracked Threads

Braided lines fasten to faucet inlets and valve outlets via threaded nuts. A washer inside each nut compresses against the outlet or inlet to form a watertight seal. A loose nut allows water to seep around the washer and leak at the joint between the nut and the threads. An excessively tightened nut might crack threads and allow water to leak. In general, plumbers tighten braided lines' compression nuts approximately one-quarter rotation beyond hand tight.

Thread Sealant

Braided lines' compression threads differ in design from standard pipe threads. Whereas standard pipe threads require a coating of pipe thread sealant to create a watertight seal, braided lines' compression threads create a watertight seal with their plastic washers. Applied to compression threads, sealant might spread or jam threads, to create a leak. If you find thread sealant on your braided line's threads, remove the nuts and clean the sealant from both the braided line and the valve or faucet inlet.

Crimp Collar

Supply line nuts connect to the body or hose of the assembly via a crimped collar. Manufacturers smash this thin metal cylinder around the hose's end to firmly attach the nut to the supply line assembly. Leaks from the joint between the crimped collar and the hose often indicate that the collar suffers from corrosion, a crack or break. A braided line with a leak at its collar generally requires replacement.

Punctures and Hose Breaks

Although constructed of sturdy steel, braided supply lines' metal sheathes occasionally crack or develop punctures. Excessive twisting often causes braided lines to crack. To prevent cracks from twisting, remove the braided line during plumbing repairs, rather than forcing it out of the way. Several objects are capable of puncturing braided supply lines, including sharp tools and fasteners, such as nails and screws. Cracked or punctured supply line hoses generally require replacement.